BULLETIN OF THE 



OMMIOFAffldTIi 



No. 131 



Contribution from the Bureau of Entomology, L. O. Howard, Chief 

 September 10, 1914. 



REPELLENTS FOR PROTECTING ANIMALS FROM 

 THE ATTACKS OF FLIES. 1 



By H. W. Gkaybill, D. V. M., 2 

 Assistant Zoologist, Zoological Division, Bureau of Animal Industry. 



INTRODUCTION. 



During the warm season of the year cattle, horses, and mules suffer 

 a great deal of annoyance and more or less injury as the result of 

 the attacks of various biting flies, and numerous requests are received 

 in this department concerning methods of relieving the animals from 

 these attacks. The flies that cause the greatest annoyance to domes- 

 tic-animals are the stable fly {Stomoxys calcitrans L.) and the horn- 

 fly (Lyperosia irritans L.). The horseflies (Tabanidse) are of some 

 importance and individually their attacks are sanguinary, but they 

 are not the cause of as much injury as either of the two species of 

 muscids that have been mentioned. The bot flies (OEstridse) affect- 

 ing horses, cattle, and sheep are not biting flies and only visit these 

 animals to deposit their eggs. The larvae of these flies, however, are 

 parasitic and are the cause of considerable annoyance and more or 

 less loss, and for this reason repellents are sometimes applied to ani- 

 mals to prevent the adults from depositing their eggs. In the case 

 of the horse and the ox, parasiticides are applied to the skin to 

 destroy the eggs of bot flies that have already been deposited. 



The screw worm (Paralucilia macellaria Fab.) likewise is not 

 parasitic in its adult state, and visits animals only to deposit its eggs 

 in wounds where the larvse, when they emerge, may find nourishment 

 and complete their growth. There are also various other species of 

 flies that may deposit their eggs in wounds and whose larvse become 

 parasitic. 



In the United Kingdom and Holland a bluebottle fly (Lucilia 

 sericata Meig.) deposits its eggs on the soiled wool about the anus, 



1 The investigations reported in this paper were undertaken by the Bureau of Ani- 

 mal Industry incidentally during the progress of other investigations concerning stock 

 dips. Although comparatively few repellents were tested, it is believed that the data 

 obtained concerning substances which may be applied to live stock to protect them 

 from flies are of interest and value to the live-stock industry. 



2 Resigned, April 16, 1914. 



51293°— Bull. 131—14 1 1 



